The present invention relates to a movable body driving apparatus. In particular, it relates to a movable body driving apparatus having a structure in which a motor can be individually removed easily, for example, in a state where a vehicle or the like is rigged with the apparatus in order to open and shut a door of the vehicle automatically.
It is commonly known to utilize a linear motor in a movable body driving apparatus that is used to open and shut a door of a vehicle or the like. When the movable body driving apparatus is a movable coil type linear motor driving apparatus, the sum of the length (generally 600 mm to 900 mm) of a door stroke and the length of a movable part is structurally equal to the length of a stationary part. Accordingly, because the mass of the apparatus increases and the area occupied by the apparatus increases compared with a rotation type driving apparatus, there is a problem that it takes a lot of time, effort and trouble to rig a vehicle with the apparatus. On the other hand, when the moveable body driving apparatus utilizes a permanent magnet type movable coil type linear motor, there is a problem in that the linear motor is expensive because of a large amount of rare-earth permanent magnet that must be used in the permanent magnet.
Therefore, due to the fact that a rotation type motor is adapted to a compact design, there has been proposed a movable body driving apparatus including a turning device made of a combination of a rack of a linear door driving apparatus and a pinion, and a permanent magnet synchronous motor as a flat motor attached to the pinion of the turning device (e.g. see JP-A-2007-297796 (paragraphs [0019] to [0022] and FIG. 3).
FIG. 7 is a view showing a permanent magnet synchronous motor formed so as to be close to a flat motor used in such a movable body driving apparatus designed compactly according to the related art. The motor 1 shown in FIG. 7 is a flat motor but the size of the motor is changed from that according to the related art. Moreover, an encoder 2 is externally provided and attached to an encoder attachment plate spring 3. A pinion 5 is fixed to a motor shaft 4, upper and lower racks 6a and 6b are engaged with the pinion 5, and a pinion and rack frame 7 supports the pinion 5 and the upper and lower racks 6a and 6b and other parts in the pinion and rack frame 7 as shown in FIG. 7 is the same as in the related art.
As described in the related art, when the motor 1 in FIG. 7 rotates in one of opposite directions, the pinion 5 fixed to the motor shaft 4 rotates in one of opposite directions to thereby move the upper and lower racks 6a and 6b in opposite lateral directions (opposite cross directions in FIG. 7) respectively. Though not shown, left and right doors are attached to the upper and lower racks 6a and 6b through an upper rack linker and a lower rack linker, respectively. When the upper and lower racks 6a and 6b move in opposite lateral directions respectively, the left and right doors are opened or closed.
FIG. 8 is a view showing a state where the motor 1 is detached from the pinion 5 and rack frame 7. When the motor 1 needs to be repaired, the motor 1 is detached from the pinion and rack frame 7 in this manner. However, because the pinion 5 engaged with the upper and lower racks 6a and 6b is fixed to the motor shaft 4, the motor 1 cannot be removed by itself, but instead, the pinion 5 is removed together with the motor 1.
If the pinion 5 is removed together with the motor shaft 4 from the pinion and rack frame 7 whenever the motor 1 is repaired as described above, displacement occurs every time in the relative positions of the upper and lower racks 6a and 6b disengaged from the pinion 5. If displacement occurs in the relative positions of the upper and lower racks 6a and 6b as described above, it is necessary to align the displaced positions of the upper and lower racks 6a and 6b and input information of the alignment to a controller which controls door opening/closing when the repaired motor 1 or a new motor 1 for exchange is attached to the pinion and rack frame 7.
The motor 1 may be overhauled relatively frequently for periodic inspection. If it is necessary to align the displaced positions of the upper and lower racks 6a and 6b and input the alignment information to the controller whenever the motor 1 undergoes periodic inspection, a lot of time, effort and trouble occurs each time the motor must be removed.